由多个地震震源机制解求川滇地区平均应力场方向  

DETERMINATION OF DIRECTIONS OF THE MEAN STRESS FIELD IN SICHUAN-YUNNAN REGION FROM A NUM- BER OF FOCAL MECHANISM SOLUTIONS

作　　者：钟继茂[1] 程万正[2] 

机构地区：[1]福建省地震局,中国福州350003 [2]四川省地震局,中国成都610041

出　　处：《地震学报》2006年第4期337-346,共10页Acta Seismologica Sinica

基　　金：国家重点基础研究发展计划课题(2004CB418404);地震科学联合基金(105004)资助

摘　　要：基于震源断层面解的空间取向和断层滑动方向,写出相应力轴张量在地理坐标系中的表达式,进而给出计算平均力轴张量及主值的方法,即通过求解相应的本征方程得到.对使用多个震源机制解的T,B,P轴参数计算平均应力场的方法,以用滑动方向拟合法反演富蕴、唐山地区平均应力场数据进行验证,二者结果一致.选择具有地震构造意义的地块或地震带内大量地震的震源机制解研究区域平均应力场.根据川滇13个地震带(区)的256次中强地震的震源机制解,给出了各带(区)应力张量的定量分析结果.该方法算法简便,使由大量地震震源机制解资料分析构造应力场的方法走向定量化.Based on the spatial orientation and slip direction of the fault plane solutions, we present the expression of corresponding mechanical axis tensor in geographic coordinate system, and then put forward a method for calculating average mechanical axis tensor and its eigenvalues, which involves solving the corresponding eigenequation. The method for deducing mean stress field from T, B, and P axes parameters of a number of focal mechanism solutions has been verified by inverting data of mean stress fields in Fuyun region and in Tangshan region with fitting method of slip direction and both results are consistent. To study regional average stress field, we need to choose a population of focal mechanism solutions of earthquakes in the massifs where there are significant tectonic structures. According to the focal mechanism solutions of 256 moderate-strong earthquakes occurred in 13 seismic zones of Sichuan-Yunnan region, the quantitative analysis results of stress tensor in each seismic zone have been given. The algorithm of such method is simple and convenient, which makes the method for analyzing tectonic stress field with large amount of focal mechanism solution data become quantified.

关 键 词：力轴张量 震源机制 平均应力场 川滇地区 

分 类 号：P315.33[天文地球—地震学]